The unusual addition of coriander and cumin seeds to add a hint of fragrant flavour, combined with the tart gherkins just works here. The trick of adding the diced gherkin in the patties (Jamie O does not do this) is from my friend Kylie in Freshwater, Sydney – served for lunch to a crowd and cooked on the BBQ, I had to ask her what made them different yet so yum, this was it! They also helped keep the burgers moist. Thank-you Kylie McFarlane!